FIGS. 14A to 14E show a conventional method of forming a programmable impedance cell.
FIG. 14A shows the formation of a first ion conductor layer 1402-A on a bottom electrode layer 1404.
FIG. 14B shows the formation of an active metal layer 1406 on first ion conductor layer 1402-A. Active metal layer 1406 may be formed in the presence of ambient air. Consequently, reaction products may be created due to components of such an ambient air environment. For example, water vapor or oxygen (or other species) within the air may create undesirable, or uncontrolled reaction products (one shown as 1408) within active metal layer 1406 or ion conductor layer 1402-A.
FIG. 14C shows the formation of a second ion conductor layer 1402-B on an active metal layer 1406.
FIG. 14D shows the incorporation of active metal layer 1406 into ion conductor layers 1402-A and 1402-B. Reaction products (e.g., 1408) may remain within a resulting ion conductor layer 1410.
FIG. 14E shows the formation of a top electrode 1412 on ion conductor layer 1410.
Uncontrolled or undesirable products (e.g., 1408) may lead to inadequate or undesirably variable programmable resistance responses for ion conductor layer 1410. Alternatively, such products (e.g., 1408) may affect the incorporation of active metal layer 1406 into ion conductor layers (1402-A and 1402-B) in an uncontrolled or unpredictable sense.